where \(r_i,r_j\)  are the rewards received by agent \(i\)  and \(j\)  respectively, \(r^{ref}_i,r^{ref}_j\)  are the reward references of each agent consisting of the sum of the last two rewards, \(\alpha ,\beta \)  are the disadvantageous/advantageous inequity parameters respectively (see [1]}). The fact that \(r^{ref}_i\)  considers the rewards of the last two episodes of agent \(i\)  differs from [1]} and it was important for the obtained results.
